The former One Direction member is currently on his first-ever solo headline tour.
Vocalist-guitarist Russell Moore has also joined the group.
The Live Nation-produced tour launches Feb. 9 in Melbourne.
The singer launched her 'Brat' tour at the northern city's 23,500-capacity Co-op Live venue.
The festival will be held at the city's Heaton Park next June, with a full lineup to follow in January.
The trek grossed nearly $210 million and sold 1.7 million tickets.
The enduring pop star leads the October monthly report in stadiums and arenas as she finishes an 18-month marathon of concerts.
The run of shows will conclude with a date at London's Wembley Stadium in July.
The Brat star will headline London's LIDO Festival in Victoria Park in June.
The Gallagher brothers have announced more shows for their Live ‘25 reunion tour next year.
